Probably have to scrape it off with a razor blade. You might try acetone as a last ditch solvent method, but that’s it’s own bag of worms.

I remember when I learned about this, I was working on an absurdly large project on my own. I was lost in all the details and losing hope of ever finishing. I was working on the backend API when I learned of this and took the time to implement the 418 response. It felt silly and brought the fun back to the project.